Process for Preparing a Diene Copolymer Comprising a Polyether Block, Diene Copolymer Comprising a Polyether Block, Reinforced Rubber Composition and Tire

A process for preparing a diene block copolymer, of which at least one of said blocks is constituted of a diene elastomer and at least the other of said blocks is constituted of a polyether, wherein the process comprises a step of reacting a living diene elastomer with a functionalizing agent having a functional polyether block of number-average molecular weight approximately from 150 to 5000 g/mol, represented by the general formula I:

• R1A)m Formula I
• in which:
• R1 represents a C1-C15 alkyl, C6-C15 aryl or C7-C15 aralkyl hydrocarbon-based derivative of valency m;
• m is an integer from 1 to 4;
• and
• A represents, identically or differently when m is greater than 1, the group of general formula II
• in which:
• R2 represents a C1-C10 alkylene radical;
• R3 represents a divalent C1-C50 alkyl, C6-C50 aryl or C7-C50 aralkyl hydrocarbon-based derivative;
• R4 represents a C1-C50 alkyl, C6-C50 aryl or C7-C50 aralkyl radical;
• X represents, identically or differently when i is equal to 0 or 1, a group chosen from a halogen atom and a group of formula —OR5 in which R5 represents a C1-C18 alkyl, C5-C18 cycloalkoxyl or C6-C18 aryl radical;
• n is a number greater than 1, so that the polyether block has a number-average molecular weight approximately from 150 to 5000 g/mol;
• and
• i is an integer from 0 to 2.